Metabolomics is the quantitative measurement of all metabolites over time. The objective of this Core will be to quantify metabolites in tissues, biological fluids, cells or organelles that are affected by changes in either heme synthesis or metal concentrations. Members of the Utah CEMH have special expertise in the analysis of heme and porphyrin metabolites and of metals (not exactly a metabolite). We have performed determinations of these metabolites and elements for investigators outside of Utah. We propose to extend our analysis to a wide variety of other metabolites, including amino acids, organic acids, monosaccharides, disaccharides, alcohols, and aromatic amines and lipids. Specific attention will be given to mitochondrial metabolites for two reasons. First, malregulation of heme synthesis and many iron disorders affect mitochondrial metabolism. Second, analyzing the relatively restricted number of mitochondrial metabolites will provide proof of principle for metabolomic analysis. Careful analyses of all reactions known to occur in mitochondria have led to the predictions of 164 and 230 metabolites in yeast and human mitochondria, respectively. Separation, identification and quantification of approximately 200 metabolites is realistically achievable using commercially available instruments.